Written by Bert Pschunder
Ames Lake was formed at the end of the last Ice Age in the Puget Sound area. At that time, a large ice block sat in a depression. As it melted, the sand and rock got moved by the streams of meltwater. The water flowed off the side of the ice block, as though the lock was a hill, and deposited the sand and rock around the rim of the ice block. These deposits are called ice contact stratified drift. It’s part of the reason we have a rim of higher ground around the lake.
Another reason for the higher ground is the glacial till deposits, which preceded the ice contact stratified drift. The glacial till included a mixture of silt, sand, and rock, which was deposited under the larger ice sheet that moved down from the north. Thousands of feet of glacial ice compacted the till, which is why it’s so hard to dig!